Dragon,
I think many people confuse Tasers for the more common "stun guns". The Taser C2 that I carry, and the X26, have several features that the cheaper generic "stun guns" may lack.
First is what i see as the deterence features which are the intergrated LED lights and aiming laser. Most criminals are looking for a unarmed or easy target. Lighting and lazing a agressor will often result in them hesitating or breaking off an attack.
Second, while they are short range devices, they do have more range than a baton or cane. You mentioned stand off distance. The Taser C2 has a range of 15 feet. That's close but not as close as they would get with the options you mentioned. Even if the probes fail to hit their mark and the agressor closes the distance you still have the drive stun option at contact ranges.
As you corectly pointed out, they are one shot devices. Multiple threats are possible but single aggressors are probably much more likely. Of course, if multiple agressors confront me I'm not relying soly on my one shot Taser. I have other options (Pistol, OC spray, knife, etc...) Some people choose to keep a second firing cartridge on hand and plan on doing a fast reload if possible. Others choose to carry secondary devices such as OC spray or deploy a firearm should the Taser fail to stop the threat. I personally see my Taser as a accessory to my daily carry firearm which gives me options to using deadly force. It's not a replacement for the pistol but a tool I can use in addition to the pistol as the needs dictate.